I've just been watching the second episode of The Singing Detective[^]. When I feel I can do it justice I'll write a rave review of the series.
There's one effect that I really noticed for the first time tonight (I must have seen the entire series 50 times). It's in a scene where the focus moves from The Forest of Dean in 1945 to a London Hospital in 1985. On the soundtrack we hear a jet fading in as we move forward in time. It struck me as being most apposite.
Remembering back, the sound I associate with airplanes when I was a kid is of the drone produced by internal combustion engines. Living first in West Footscray and then in Seddon placed us pretty close to the flight paths for Essendon Airport in the late 1950's and 1960's and one could usually count upon hearing that droning sound. The characteristic sound of a jet came later when Tullamarine Airport opened. We'd moved house by then to St Albans but that still put us very close to the flight paths for the new airport.
My wife tells me that when US aviation shut down for the two days following the collapse of the twin towers there was a noticeable difference in the audible background here in Phoenix. I was still living in Melbourne at the time but I can well believe it. Scottsdale Airport isn't very far away and the sky here is thick with planes at all hours of the day.
When we went for that hike in the Superstition Mountains a few months ago one of the things I noticed was that, even some miles away from 'civilisation' there was an almost continuous if very faint background noise of jets flying overhead. You can't see them but you can hear them.